[lupo]

Here's how I would deal with that and how I have dealt with it in the past. Clean it up best you can acid wash all the bare steel. Apply two coats of the aluminum pigmented permanent rust sealer. This'll seal up the pinholes and seems from further leakage and level up the pitting. This will put a waterproof and airtight seal over your repair. Prime it with your epoxy primer and paint. My general rule of thumb is anywhere it rusted in the past like cab corners is likely to rust again in that area. When you combine a base primer that is airtight and a epoxy primer then a urethane top coat this is the most anticorrosive system in the industrial coatings industry.